I noticed that Michigan has been added to the list of states--thank you, John! However, there seems to be an issue with this summit. The true summit appears to be directly north of where it's currently marked, at the tiny contour atop the steep bluffs running into Lake Michigan; both my own visits there and the topo map seem to indicate this. This'd make the true elevation at least 968' (and based on what I remember of the summit area, it probably rises to about 970').
The summit is very much worth a visit if you're in the area, as it entails panoramic views out over the Manitou islands and is easily accessible by trail. I've seen many a sunset from the top, and it's by far one of my favorite places in the state...